Titanium sulphuric acid compounds



I Patented Nov. 14,. 1 933 I "TITANIUMiSULPHII RIC' ACID COMPOUNDS Ludwig Teichmann, Leverkusen-on the-Rhine,

and Franz Specht, Cologne-.on-the-Rhine,Germany, assignors to I. G. Farbenindustrie Aktiengesellschaft, Frankfort-on-the-Main, Germany No Drawing. 'A'pplication January 6, 1931, Serial No. 507,040, and in Germany January 15, 1930 2 Claims. (01. 23-117) The present inventionrelates to a process of preparing compounds consisting of titanium dioxide and sulphuric acid in such proportions that 1 mol of titanium dioxide is bound to 0.5-0.9 mol 5 of sulphuric acid.

The new products are obtainable by treating a solution of titanium dioxide in sulphuric acid with a compound precipitating the sulphuric acid as a diificultly soluble sulphate. Such compounds are, for example, earth alkali metal-salts, -oxides and -hydroxides, lead salts and also organic compounds as, for instance, benzidine.

For preparing the products in question We 7 start with a decomposition of a titanium ore -15. (ilmenite) with sulphuric acid. This solution contains for about 1 mol of titanium dioxide 1 mol of sulphuric acid. Into this solution a sul .phuric acid binding agent, such as for instance calicum carbonate, is introduced in such a pro- .2 portion as is equivalent to a part of the sulphuric acid, for'instance, 0.5. to 0.1 mol. Calcium sulphate precipitates, and the resulting solution is concentrated in vacuo until. a sirup'is obtained, which can be diluted with water for tanning or weighting purposes in the known manner. Also dry products can be obtained by evaporating "the solution in, vacuo or by drying the solution on a drum dryer. The dry products, thus obtained are white crystalline masses which 'are easilypulverable and which dissolve in water without.

splitting ofi titanium dioxide. 7

It is obviously also possibleto combine the process as described in the examples of appli' cation Serial No. 417,000, filed December 27, 1929, v with the present process, for example, by carry i V 7 In the samemanner as in Example 2, by stirring strontium-carbonate into a solution of 176.2

ing out the neutralization to a desired degree by means of calcium carbonate'and then finally adjusting the desired basicity bymeans of sodium hydroxide or carbonate, or'by effecting the: $40 desired result in the reverse order. 7

The solution thus obtained contains sodium sulphate which, as stated in application Serial No. 417,000, favorablyinfluences the pH concentration of the solution and the stability of the solution against hydrolysis.

In contradistinction to the invention described .in application Serial'No. 417,000, the present invention has the advantage that products are 'ob-' tainable which only'consist of titanium dioxide and sulphuric acid and which have no superfluous constituents, as for instancefsodium sulphate which alwaysis containedin the products described in application Serial No. 417,000. These solutions have the disadvantage over concen- .-5 trated titanium dioxide-sulphuric acid solutions (containing'besides sodium sulphate) that sodium sulphate crystallizes out slowly and that the content of titanium dioxide in this tanning solution is thereby altered; when solid substances are produced tanning salts rich in'sodium sulphate 13.0 are obtained. I 1

' The invention is illustrated by the following examples without being restricted thereto:-

Example 1 Into a solution containing per liter 127 grams of TiOz and s50 grams of sulphuric acid (free and combined with titanium), are stirred 315 grams of calcium carbonateper liter of solution. The solution, after being separated from the prcipi- .7,-0- tate, still contains 128 grams of T102 and 149 ff gramsof1-I2SO4= 5% basicity, (1TiOSO411I-IzSOr being designated as 0% basic and 1TiO2IOI-I2SO4 as basic) The precipitate. is covered witha 10% sulphuric acid, this is drawn off and added 75 to a fresh solution. In this way practically no "'f TiOz islost.

. Example 2 of TiOz and 187.3 gramsof sulphuric acid (free and combined with titanium) are stirred 70 grams of calcium carbonate in the form of a paste per liter 'of solution. In the filtrate from the precipitate formed there are 101.3 grams of TiOzper 35 liter and.98.0 grams of H2SO4 per liter=0.79 molecule H2SO4:1TiO2 (calculated from the quantity of CaCOa added, 0.77 molecule H2304).

. Example 3 grams of TiOz per liter and 269.5 grams of H2804 per liter a solution of 163.2 grams of TiOz per liter and 150.3 grams of H2804 per liter is produced: .95

approximately 0.75 of a 'molecule H2SO4I1T1O2. M This solutionis evaporated. at 60 C. and under 2 containing 0.79 molecules of HzSO411TiO2 is 'made up to a cencentration of 68 grams of H2804 per liter by'the addition of 27.8 grams NazCO3 per liter. This solution is evaporated in vacuo at 50. C. and 60 mms. Hg. whereby a solid salt is.

obtained containing 39.5% of TiOz, 26.8% of Into-a solutioncontaining per liter 127.5 grams 80 I of sulphuric acid upon one mol of titanium dioxide.

2. In a process of preparing tanning and v Weighting agents from aqueous solutions of titaniumsulphuric acid compounds the steps which comprise adding to an aqueous sulphuric acid solution of titanium dioxide, containing for about one mol of titanium dioxide one mol of sulphuric acid, such a quantity of calcium carbonate that the remaining solution contains 0.5-0.9 mol of sulphuric acid upon onemol of titanium dioxide.

LUDWIG: TEICHMANN.

1 FRANZ SPECHT. 

